This invention relates to a device for controlling rotations of a photosensitive drum for an electrographic apparatus.
In an electrographic apparatus which makes use of a photosensitive drum, it is necessary to rotate the photosensitive drum one turn in order to produce an electrostatic latent image thereon and then transfer such latent image to a record sheet. In this case, a step of producing the electrostatic latent image on the photosensitive drum must be effected independently of a step of transferring the electrostatic latent image to the record sheet. As a result, in the case of reproducing one or a plurality of copies from the electrostatic latent image produced on the photosensitive drum, the drum must be rotated for number of turns which is equal to number of copies set beforehand plus 1.
Many attempts have been made to provide a device which can rotate the drum for number of turns which is equal to number of copies set beforehand plus 1, but hitherto none has led to such devices which can satisfactorily control the rotations of the drum irrespective of the number of copies to be reproduced in a simple and reliable manner.